This section provides background information related to the present disclosure which is not necessarily prior art.
When beer (or other beverage or liquid or fluid) is charged with a gas, such as a carbon dioxide, to move the beer through the various supply lines, the gas is entrained to dissolve in the liquid and resides in a stable state for temperatures at or below about 30° F. The gas typically does not bubble out of the liquid, but is carried in the liquid and gives a beverage a distinctive effervescence when consumed. However, as the temperature of the fluid rises above 30° F., absent an increase in pressure on the system, the gas becomes increasingly unstable and begins to bubble or foam out of the flowing liquid. Further warming of the liquid increases the foaming effect, as the gas bubbles form and propagate downstream. Foaming is further exacerbated by disturbances in the liquid, such as the turbulence generated when the fluid is dispensed from the dispensing valve. When the liquid is warmed to 45° F. or more, such as when exposed to normal ambient room temperature, the gas becomes sufficiently unstable and so much foam is generated when it is dispensed that it is often undesirable.
One of the factors that may result in undesired increase in the temperature of the liquid is the use of a solenoid valve. In this regard, when a current is applied to the solenoid coil to actuate the valve, heat is generated that can heat the liquid flowing through the valve. This is undesirable and, therefore, a valve is needed for dispensing a liquid that does not transfer heat to the fluid during use of the valve.
Another factor that affects formation of foam in the liquid is the flow path through the valve. In this regard, if the flow path requires the fluid flowing therethrough to change direction a number of times, the amount of foam in the liquid can increase, which, as noted above, is undesirable.